The present invention relates to a chain link conveyor comprising a plurality of identical chain links hinged by transversely extending hinge pins insertable through eye part at front and rear edges of adjacent links so as to enable the hinged links to be pivotable about both a normally horizontally disposed hinge pin and, to a limited extent, about a normally vertical axis through a mid point of the hinge assembly, wherein an edge of each chain link includes two eye parts and the other edge includes one eye part for receiving the hinge pin of an adjacent link, with the opening of the one eye part making it possible by the hinge pin to be moved only during running of the conveyor. Each chain link includes a top plate arranged to support articles to be transported with the conveyor, with the top plate including a plurality of fingers separated by recesses and extending out from the front edge and rear edge of the respective links, and with at least one recess and at least one finger being disposed at a center line of the link.
Chain link conveyors of the aforementioned type include a large number of identical hinged chain links so as to form an endless conveyor. The individual chain links are configured so that the chain can be fed around drive sprockets and carrier wheels, and so that the chain can run through normally horizontally-disposed curves or bends. Chains for such conveyors are commonly known as flex-chains which are, unlike the types of chains which can run only in a straight line, and which are therefore known as straight-running chains. The invention thus relates to a flex-chain for a chain-link conveyor, wherein the chain links can be made of plastic or metal and, preferably, stainless steel.
It is a common problem when flex-chains are run in curves that the chain opens at the outer edge of the curve, which limits the size of the articles which may be placed on the conveyor. If only small openings are desired in the use of commonly-known chains for running around curves, this normally necessitates the use of curves with a large radius, which has many disadvantages.
In, for example, U.S. Pat. No. 4,676,368, a metal flex-chain for chain-link conveyors is proposed which is adapted to run in curves having radii of 20-25 cm. With such a construction relatively large openings may arise in the support surface of the conveyor.
In U.S. Pat. No. 4,754,872, a plastic flex-chain for a conveyor is proposed, wherein the top of each chain link is provided with ribs of a special configuration, so that running in curves results in a number of smaller openings in the support surface of the conveyor. However, chain-link conveyors of this type have limited application, in that such chain-link conveyors can naturally only be used for the transport of items which can be supported by the upper surface of the ribs.
In U.S. Pat. No. 4,893,709, a so-called flex-chain of the type described above is proposed; however, the coupling between the chain links is effected with a cardan link which, among other things, comprises a substantially spherical coupling part insertable in each chain link and through which the hinge pin in each link is inserted. The construction achieved hereby is complicated and has several disadvantages; namely, it is difficult to clean the chain links sufficiently, and the construction automatically results in a relatively high construction height, that is, a relatively thick conveyor which requires high side rails, etc. Furthermore, the central projection is positioned so that it extends out over the cardan link, which further increase the height of the construction and results in a relatively large opening between the projection on a link and the recess of the adjacent link.
Additionally, U.S. Pat. No. 4,893,709 proposes a configuration which is in the form of plastic chain links.